The present invention relates generally to mechanical park locking for vehicle transmissions, and more specifically, but not exclusively, to a park lock mechanism for narrow transmissions having tight packaging and weight constraints.
Park lock devices for automotive vehicle transmissions are notoriously well known as a general proposition. Transmissions have continued to evolve, and park lock devices disposed within such transmissions also need to evolve. For example, a particular transmission for an electric vehicle (EV) is quite narrow as it is positioned between an electric motor on one side and an inverter on the other side. Where many conventional park lock devices are implemented in two planes, a narrow transmission of an electric vehicle prevents implementation of such conventional solutions. Further, many conventional park lock devices include a park lock controller near the parking gear. The narrow transmission having large areas covered by the motor on one side and the inverter on the other limits such conventional location of the park lock controller.
Mechanical cooperation of the components of such transmissions preferably meet a number of operational goals in addition to provision of a park mode and a not parked mode. These operational goals in some cases are actual requirements and include resistance to park engagement while the vehicle is moving. As soon as the speed of the vehicle falls below the lock speed while park mode is commanded, the park lock device should automatically engage to safely enter into the park mode and stop the vehicle. The transmission should then remain parked until the vehicle is transitioned to the not parked mode. Irrespective of a slope on which the EV is stopped, the transmission should not provide too great of mechanical resistance to mode transition.
While not necessarily required by the narrowness of the EV transmission, systems on EVs have tight budgets for space and weight. These budget constraints work against a straight-forward implementation of a park lock device for a narrow transmission such as may be contemplated to be used in an EV. What is needed is a system and method for a park lock mechanism for narrow transmissions having tight packaging and weight constraints.